Commit Message

The previous "contains" changes caused a ~3% parsing speed impact.
Looking at the cause of those changes was interesting:
* Use of defaultdict was slower than just checking for missing entries
and setting them when needed.
* Even the "import collections" adversely affects parsing speed
* There was a missing intern function for the contains cache data
* Setting up a log object for each variable has noticeable overhead
due to the changes in the code paths uses, we can avoid this.
* We can call getVarFlag on "_content" directly within VariableParse
for a noticeable speed gain since its a seriously hot code path.
This patch therefore tweaks the code based on the above observations to
get some of the speed back.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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